Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology Lab > Lab Exam 3 > Flashcards

Lab Exam 3 Flashcards

1
Q

what are examples of simple stain?

A

methylene blue (blue)
safranin (pink)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are examples of differential stains?

A

malachite green (green)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the four steps of differential staining?

A
  1. primary stain - colors the target cell
  2. mordant - helps color stick in target cells
  3. decolorizer - removes color from background and non-target cells
  4. counterstain - stains non-target cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the four chemicals used for gram stain?

A
  1. primary stain: crystal violet
  2. mordant: iodine
  3. decolorizer: acetone/alcohol
  4. counterstain: safranin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what were the target and non-target cells used in gram stain? what color should they have been?

A

target: Staphylococcus aureus - purple
non-target: Escherichia coli - pink

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the four chemicals used for acid fast stain?

A
  1. primary stain: basic fuchsin
  2. mordant: phenol + dimethyl sulfoxide
  3. decolorizer: acid-alcohol
  4. counterstain: methylene blue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what were the target and non-target cells used in acid fast stain? what color should they have been?

A

target: Mycobacterium smegmatis - pink
non-target: Staphylococcus aureus - blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are the four chemicals used for endospore stain?

A
  1. primary stain: malachite green
  2. mordant: steam
  3. decolorizer: distilled water
  4. counterstain: safranin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what were the target and non-target cells used in endospore stain? what color should they have been?

A

target: endospores - green
non-target: vegetative cells - pink

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the primary stain in capsule staining?

A

congo red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the purpose of the acid-alcohol for the capsule stain? how is this different than how it was used for acid-fast?

A

In capsule staining, acid-alcohol chemically fixes the cells to the slide

In acid-fast, acid-alcohol is used as the decolorizer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the secondary stain used in capsule staining?

A

carbol fuchsin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do capsules appear at the end of capsule staining?

A

background will be dark blue/purple and magenta
capsules will look like a clear halo around the pinkish color of the bacillus shaped cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what was the target bacteria in capsule stain? what color?

A

Klebsiella pneumoniae - mostly colorless

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the purpose of streak plating?

A

to produce pure, isolated colonies from a mixed sample

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

why do we flame the loop in between each zone?

A

to reduce the number of microbes as we progress steps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what antibiotic was most and least effective?

A

Most: Chloramphenicol
Least: Bacitracin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what antiseptic was most and least effective?

A

Most effective – 1% formaldehyde
Least effective – 70% isopropyl alcohol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Which bacterial type is the most and least susceptible to antibiotics?

A

most susceptible: Mycobacterium smegmatis
least susceptible: Escherichia coli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

which bacterial type is the most and least susceptible to antiseptics?

A

most susceptible: Mycobacterium smegmatis
least susceptible: Escherichia coli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what does the death zone of a susceptible organism look like?

A

large death zone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what does the death zone of a resistant organism look like?

A

small/no death zone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is the equation to convert Celsius to Fahrenheit

A

°F = (°C x 1.8) + 32

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is refrigerator temp in Celsius?

A

4 °C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what is room temp in Celsius?

A

25 °C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what is body temp in Celsius?

A

37 °C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what is the definition of selective media?

A

inhibits growth of unwanted microbes (only the selected microbes live)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is the definition of differential media?

A

allows organisms to grow but the added chemicals make them look different (they change different colors and/or precipitate is visible)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what were the three specific plates that we used in our lab?

A

MSA: Mannitol salt agar
EMB: Eosin methylene blue
MAC: MacConkey agar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

where were the colors of the MSA, EMB, and MAC plates before inoculation?

A

MSA: red
EMB: dark purple
MAC: raspberry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

which plate used in lab this semester was not selective or differential?

A

TSA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

which organisms used in the S&D exercise are Gram + ?

A

Staphylococcus aureus
Staphylococcus epidermidis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

which organisms used in the S&D exercise are Gram - ?

A

Escherichia coli
Enterobacter aerogenes
Proteus vulgaris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

How is MSA selective?

A

selects for gram +
selects against gram -

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

how is EMB selective?

A

selects for gram -
selects against gram +

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

how is MAC selective?

A

selects for gram -
selects against gram +

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

How is MSA differential? (fermentation?)

A

differential for mannitol fermentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

how is EMB differential? (fermentation?)

A

differential for lactose fermentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

how is MAC differential? (fermentation?)

A

differential for lactose fermentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

what are the possible bacteria and colors produced by inoculating MSA plate?

A

fermenter: growth turns yellow (Staphylococcus aureus)
nonfermenter: growth remains red (Staphylococcus epidermidis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

what are the possible bacteria and colors produced by inoculating EMB plate?

A

strong fermenter: growth turns shiny metallic green (Escherichia coli)
weak fermenter: growth turns pink around the edges of colonies (Enterobacter aerogenes)
nonfermenter: growth remains dark purple (Proteus vulgaris)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

what are the possible bacteria and colors produced by inoculating MAC plate?

A

strong fermenter: entire plate turns bright pink (Escherichia coli)
weak fermenter: growth turns light pink with precipitate and background turns light brown (Enterobacter aerogenes)
nonfermenter: entire plate turns brown (Proteus vulgaris)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

what genus is used for the gram + sphere project?

A

Staphylococcus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

what are the potential species used within the gram + sphere project?

A

Staphylococcus aureus
Staphylococcus capitis
Staphylococcus epidermidis
Staphylococcus haemolyticus
Staphylococcus lentus
Staphylococcus saprophyticus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What type of media was used to test for growth at elevated temperature?

A

TSB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

what was a positive/negative result for the test for growth at elevated temperature?

A

positive: turbid = indicated that growth was present
negative: clear = growth not present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

what tool did we use to inoculate the 45 degree experiment?

A

cotton swab

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

what does the urea agar slant test for?

A

urease production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

what tool was used to inoculate the urea agar slant?

A

loop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

what is the original media color of urea agar slant?

A

peach color

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

what is the weak acid/base pair that is produced by urease activity?

A

carbon dioxide = weak acid
ammonia = weak base

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

what gives a pos/neg result in the urea agar slant?

A

pos: hot pink color change = ^ pH
neg: yellow color change = v pH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

what was the reaction for the substrate and products of the urea agar slant?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

what does the Vogel Johnson Agar test for?

A
  • mannitol fermentation
  • coagulase production
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

what chemicals are in Vogel Johnson Agar? what do they serve as?

A

tellurite and lithium chloride
selective chemicals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

what tool and what technique is used within the Vogel Johnson Agar experiment?

A

cotton swab
zag plating technique

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

what shows a pos/neg result for mannitol fermentation within the Vogel Johnson Agar?

A

pos: yellow color change
neg: remains red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

what shows a pos/neg result for coagulase production within the Vogel Johnson Agar?

A

pos: black colonies (tellurite gets reduced to tellurium)
neg: no black colonies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

what is the enzyme associated with the Vogel Johnson Agar?

A

coagulase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What does the Blood agar plate test for?

A

hemolysin production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

What color is the blood agar plate before inoculating?

A

red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What does the blood agar plate contain to give it its color?

A

5% sheep’s blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What tools did we use to inoculate the blood agar plate? what technique?

A

Cotton swab
Zag plating technique

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What is the indication of a positive result for the blood agar plate?
What does this indicate?
What is the pattern of growth called?

A

Red color disappears under colonies
Indicates that hemolysin production occurred
Beta pattern = clearance zones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

What is the indication of a negative result for the blood agar plate?
What does this indicate?
What is the pattern of growth called?

A

No color change (growth remains red)
Indicates no hemolysin was produced
Gamma pattern = no clearance zone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

What kind of molecule is trehalose?

A

plant carbohydrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Which tool is used to inoculate an agar stab?

A

needle

68
Q

What is the name of the toxin that destroys red blood cells?

A

hemolysin

69
Q

What does the trehalose stab test for?

A

trehalose fermentation

70
Q

what color was the trehalose stab before inoculating?

A

red

71
Q

what was the pH indicator of the trehalose stab?

A

phenol red

72
Q

what was pos/neg result for trehalose stab?

A

pos: yellow color change = v pH
neg: color remains red = neutral

73
Q

What did the sodium chloride broth test for?

A

Growth in high salinity media

74
Q

What was the color of the sodium chloride broth before incoluation?

A

purple

75
Q

what was the pH indicator of the sodium chloride broth?

A

bromocresol purple

76
Q

What tools did we use for the sodium chloride broth?

A

loop

77
Q

What did a pos/neg result look like and indicate for the sodium chloride broth?

A

Pos: yellow color change = decrease in pH/ growth was present
Neg: remains purple = neutral/ no growth

78
Q

What type of agar is used to screen for antibiotic sensitivity of our unknown? what is the test called? what plating technique was used?

A

TSA
Novobiocin resistance test
Lawn plate technique

79
Q

How does novobiocin inhibit bacterial growth?

A

Novobiocin is an antibiotic that acts as DNA synthesis inhibitor to bacteria

80
Q

What would a pos/neg test result for novobiocin resistance look like?

A

pos: no death zone = resistant
neg: large death zone >4 mm = susceptible

81
Q

Which form of metabolism utilizes nitrate salt as a terminal electron acceptor?

A

anaerobic respirator

82
Q

Is nitrate an oxidized or a reduced salt? what does this mean?

A

oxidized salt
it can accept electrons

83
Q

what is the equation for nitrate being successfully oxidized in the nitrate test?

A
84
Q

Which of these reduced products are gases?

A

nitrous oxide (N2O)
nitrogen gas (N2)

85
Q

What is the function of a Durham tube?

A

to trap any potential gasses

86
Q

Is the presence of bubbles in the Durham tube positive or negative for nitrate reduction?

A

positive

87
Q

what is a pos/neg result for the nitrate broth test?

A

pos: color change to red and possibly gas bubbles formed inside Durham tube
Neg: color remains clear and no bubbles

88
Q

what did the nitrate broth test for?

A

tests for nitrate respiration

89
Q

Gelatin is what type of biological molecule?

A

protein

90
Q

What is the name of the enzyme that hydrolyzes gelatin?

A

protease

91
Q

How did we inoculate the gelatin agar so that it could be incubated?

A

used needle

92
Q

If we were to analyze the tubes for gelatin hydrolysis directly after removing the cultures from the incubator our results would be incorrect. What do we need to do before analyzing the results of our hydrolysis test?

A

allow them to chill

93
Q

Briefly describe the appearance of a tube that is positive for gelatin hydrolysis.

A

pos: liquid after chilled = break down into amino acids occurred
neg: solid after chilled = break down did not occur

94
Q

how do black colonies form in the Vogel Johnson Agar test?

A

tellurite gets reduced to tellurium when coagulase is present

95
Q

What concentration of NaCl is used in our hypertonic broth?

A

6.5%

96
Q

what are a few of the potential genera used in the gram - rod unknown experiment?

A

Citrobacter freundii
Enterobacter aerogenes
Escherichia coli
Klebsiella pneumoniae
Proteus vulgaris
Pseudomonas aeruginosa

97
Q

What type of media was used for the catalase test?

A

TSA
(In a slant)

98
Q

what is the function of catalase?

A

detoxify hydrogen peroxide

99
Q

Which substrate is broken down by catalase?

A

Hydrogen peroxide (H2O2)

100
Q

what does the catalase broth test for?

A

catalase production

101
Q

write out the complete catalase reaction, including the names and molecular formulas of all substrates and products.

A
102
Q

what does a pos/neg test look like for the catalase test?

A

pos: bubble formation after H2O2 is added
neg: no bubbles formed after H2O2 is added

103
Q

Which product of catalase activity is responsible for the visible reaction?

A

oxygen gas

104
Q

what is a pos/neg result for the simmons’ slant?

A

pos: blue color change
Neg: color remains green

105
Q

What color is the Simmons’ slant before it is inoculated?

A

green

106
Q

what does the Simmons’ slant test for?

A

citrate utilization
ammonium utilization

107
Q

what is the pH indicator of the Simmons’ slant?

A

bromothymol blue

108
Q

What is the carbon source in the Simmons’ slant?

A

citrate

109
Q

What is the nitrogen source in the Simmons’ slant?

A

ammonium

110
Q

How does nutrient utilization affect the pH of the Simmons’ slant? what happens to the ammonium as well?

A

citrate utilization removes citrate (acidic) from media which increases pH
ammonium (NH4+) gets reduced to ammonia (NH3)

111
Q

What does the abbreviation ‘SIM’ stand for?

A

S = sulfide
I = Indole
M = motility

112
Q

Which of the three tests did we not record data for? why?

A

motility
because some results would be black in color and would be too hard to see microbes being motile

113
Q

Which amino acid is degraded to produce ‘S’?

A

cysteine

114
Q

What is the enzyme that is responsible for ‘S’?

A

cysteine desulferase

115
Q

What are the three products that are produced as part of ‘S’? (show entire reaction including enzyme)

A
116
Q

Which specific product of the three is detected by ‘S’?

A

hydrogen sulfoxide

117
Q

what is a pos/neg result for ‘S’ test?

A

pos: black color change
neg: no color change (remains plain agar)

118
Q

Which amino acid is degraded to produce ‘I’?

A

tryptophan

119
Q

What is the enzyme that is responsible for ‘I’?

A

tryptophanase

120
Q

What are the three products that are produced as part of ‘I’? (show entire reaction including enzyme)

A
121
Q

Which specific product of the three is detected by ‘I’?

A

indole

122
Q

What reagent is used to test for ‘I’?

A

Kovac’s reagent

123
Q

what does a pos/neg look like for ‘I’ test?

A

pos: red ring on top of stab
neg: no color change but drops of reagent remain yellow

124
Q

what does the oxidase slant test for?

A

cytochrome oxidase utilization

125
Q

what tools did we use for the oxidase test? what type of media is it?

A

loop
TSA slant

126
Q

Where specifically is cytochrome oxidase located? What is the protein cytochrome oxidase normally used for?

A

used in ETC (electron transport chain)
transfers electrons from cytochrome C (protein) into oxygen

127
Q

what is the reaction associated with oxidase test?

A
128
Q

what type of reagent is used to interpret oxidase test? what color is it initially?

A

oxidrops (a reducing agent) - light purple

129
Q

what is a pos/neg result for oxidase slant test?

A

pos: dark purple color change w/in 20 seconds
neg: no color change w/in 20 seconds (drops remains plain light purple)

130
Q

What kills Gram + & some Gram – in the Brilliant Green Agar?

A

brilliant green dye

131
Q

what tools did we use to inoculate the Brilliant Green agar? what plating technique?

A

cotton swab
zag method

132
Q

what does the brilliant green agar test for?

A

lactose and sucrose fermentation

133
Q

what is the original color of the brilliant green agar?

A

orange

134
Q

What color is brilliant green agar that is positive for fermentation (Acidic)?
- What color is brilliant green agar that is negative for fermentation (Basic)?
- What color is brilliant green agar when the bacteria is dead (Also negative)?

A

acidic: fermenter = v pH and lime green color change
alkaline: non-fermenter = ^ pH and bright pink color change
death: inhibited by green dye/ plate remains organge + no growth

135
Q

what does the Hektoen Agar test for?

A

tests for lactose, sucrose, and salicin fermentation

136
Q

what tools did we use to inoculate the Hektoen agar? what plating technique?

A

cotton swab
zag method

137
Q

what is the initial color of Hektoen agar?

A

green

138
Q

where does salicin come from?

A

willow bark

139
Q

What is in the Hektoen agar that makes it selective? what does it select against?

A

bile
inhibits some gram -

140
Q

how many pH indicators are in the Hektoen agar?

A

2

141
Q

what are the possible results of the Hektoen agar test, and what do they mean?

A

acidic: fermenter = v pH and orange color change + growth
alkaline: nonfermenter = ^ pH and blue-green color change + growth
death: inhibited by bile/ plate remains green + no growth

142
Q

what are the two key ingredients of litmus broth?

A

skim milk
litmus powder

143
Q

what are the two functions of the litmus powder in the litmus milk broth?

A
  1. pH indicator = change color based on lactose fermentation
  2. electron acceptor = can be reduced
144
Q

what are the three reactions that can occur with the litmus powder?

A

acidic result: pos for lactose fermentation = pink color change
alkaline result: neg for lactose fermentation = color remains purple
reduction result: pos for reducing litmus powder = white band that sinks to bottom of tube

145
Q

what is the milk protein within the litmus milk broth?

A

casein

146
Q

describe peptonization?

A

when a protein is utilized

147
Q

what are the two possible reactions that can occur with the milk protein in the litmus milk broth?

A
  1. Peptonizaton - Cloudiness is removed, media becomes transparent
  2. Coagulation - Solid formation due to casein in the milk coagulating w/ acid
148
Q

describe peptonization?

A

when a protein is utilized

149
Q

what are the two possible reactions that can occur with the milk protein in the litmus broth?

A
  1. peptonization occurred = cloudiness is removed & media becomes transparent
  2. coagulation occurred = solid formation due to casein in the milk coagulating w/acid
150
Q

how will coagulation effect the broth?

A

media will become solid

151
Q

what causes the broth to coagulate?

A

casein not being used, and instead clumping with the acids

152
Q

what does MRVP stand for?

A

Methyl Red
Vogues Proskauer

153
Q

what does the MR in MRVP test for? what reagent is testing for this?

A

methyl red reagent (pH indicator) - tests for mixed acids (lactic, formic, etc.)

154
Q

what are the potential results of the MR test within the MRVP test?

A

pos: acidic result = red color change
neg: alkaline/neutral result = yellow color change

155
Q

what does the VP in MRVP test for?

A

test for alcohol fermentation

156
Q

how many days does the 2,3-butanediol test using MRVP tub incubate for?

A

5 days

157
Q

Why doesn’t 2,3-butanediol react with a pH indicator, like phenol red?

A

b/c it is neutral? (pH of 7)

158
Q

What is the exact procedure for performing the VP test in lab?

A
159
Q

What is the purpose of shaking the small tube?

A
160
Q

Which final chemical product will be created?

A

diacetyl (wat we detect)

161
Q

How long does the VP test sit before the color change is complete?

A
162
Q

What color is a positive VP test? What color is a negative test result?

A

pos: deep red color change
neg: brown color change

163
Q

What does VP test for?

A

Alcohol fermentation

164
Q

What is the specific alcohol the VP tests for?

A

2,3-butanediol

165
Q

What is the intermediate molecule involved in the VP test?

A

Acetoin

166
Q

What is the final product after adding the reagent to the VP test?

A

Diacetyl

Microbiology Lab (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions